The present invention relates to metallic foam structures and more particularly to metallic foam structures used as high pressure gas containers.
Foam structures are known in industry and the number of applications for metallic foam structures is continually increasing. For example, aluminium foam metal having a continuously connected, open celled (reticulated) geometry is available and employed in:
(a) Energy/impact adsorbers;
(b) Heat exchangers; and
(c) Lightweight composite panels.
In the gas distribution industry, the gas containers are invariably cylindrical in shape with thick walls and convex or concave ends. These known containers are simple, robust and contain maximum quantities of gas for any given weight or dimension. However, their main disadvantages are the inflexibility of their shape and weight limitations.
Foam structures have now been proposed for high pressure gas containers and, in particular, high pressure gas containers having irregular shapes, for example a non-cylindrical or spherical shape. When irregular or complex shapes are required, then foam material such as metal foams are formed typically by mixing small quantities of a gasifier e.g. titanium hydride with aluminium powder and subjecting the mixture to heat and pressure to form a sintered sheet.
The sintered sheet or a portion thereof is then placed in a mould which is then heated to higher temperatures at which the metal melts and hydrogen is released from the titanium hydride to form an even dispersion of bubbles. The bubbles are then fractured so that when placed in a thin containment material or when the outside surface is sealed in some way, for example by melting the outer aluminium layer or by casting in resin, the foam acts as a strengthening material.
It is an aim of the present invention to provide a gas container made from metal foam but in which the open-celled structure is filled with a solid gas adsorber material.
According to the present invention, there is provided a gas container made from metal foam with the spaces defined by the open-celled structure substantially filled with a solid gas adsorber material.
The solid gas adsorber material may be a zeolite, an activated carbon or a silicate and the gas container may be of any shape desired, for example the shape of a panel.
A plurality of panel-shaped gas containers may be arranged in series and connected together by connectors comprising at least one small-bore tube embedded in a foamed rubber matrix which is encompassed by a protective metallic sheath.
In one embodiment, the gas container may be made by delivering the solid gas adsorber and mixing it with molten aluminium at a temperature just before the molten aluminium goes solid. Alternatively, the molten aluminium may be poured over a matrix of particles to form a block.